1. Technical Field of the Invention
The present invention relates in general to IP television (IPTV) systems, and in particular, to commercial insertion in IPTV programs.
2. Description of Related Art
With today's widespread use of the Internet as a communication medium, packet-switched networks, such as Internet Protocol (IP), Multiprotocol Label Switching (MPLS), Asynchronous Transfer Mode (ATM) and Ethernet networks, are increasingly being used to transmit digital multimedia data or content (e.g., audio, full-motion audio/video, pictures, etc.). A typical architecture for transmitting multimedia data involves a content server (source) “streaming” the multimedia content over a packet-switched network to a client device (sink). Streaming is a process by which packets containing the multimedia content are continuously received and displayed by a recipient client device. As such, at the client device, the received data is buffered into a cache memory and continuously processed as it is received for real-time presentation to the end user.
An example of an architecture that uses streaming media technology to provide real-time multimedia content to end users is the IP television (IPTV) architecture. Within the IPTV architecture, content source nodes are digital broadcast television providers and sink nodes are typically Set-Top-Boxes (STBs) attached to television (TV) sets. In a typical scenario, a digital broadcast television provider (source) streams a television program over a packet-switched network to one or more STBs (sinks) associated with television viewers who have subscribed to receive the television program.
To distribute the television program to multiple STBs, the broadcast television source typically multicasts the television program over the packet-switched network. Multicast is a communication technique that efficiently utilizes the network infrastructure by requiring a source node to send a packet only once regardless of how many sink nodes it is being sent to. The network nodes, such as switches bridges and routers, replicate the packet, as needed, for distribution to all of the sinks. A multicast group address that identifies a multicast group is used by the source and the sinks to send and receive content. Sources use the multicast group address as the destination address in their data packets, while sinks use the multicast group address to join the multicast group by informing the network that they would like to receive packets sent to that multicast group. Once a sink joins a particular multicast group, the network constructs a multicast distribution tree to ensure that data packets sent to that particular multicast group reach all of the sinks of that particular multicast group. Therefore, multicast does not require source nodes or other intermediate network nodes to know the identities (e.g., IP addresses) of all of the sinks, only the multicast address for the group.
As is known, broadcast television providers often generate income by carrying advertising content in the form of commercials. In traditional broadcast television, local commercials are usually added to television programs at the local broadcast station, such that every viewer within a geographical area covered by the local broadcast station whose television is tuned to a particular channel broadcast by the local broadcast station receives the same commercials. Likewise, with IPTV, local commercials are usually added to multicast television programs at the local video head office (VHO), such that every viewer served by the VHO that has subscribed to a particular multicast television program receives the same commercials.
As is also known, advertisers are continually searching for avenues to provide targeted advertising to specific consumers. However, with the mass marketing approach presently provided by broadcast television (traditional and IPTV), such targeted advertising is not possible. Therefore, advertisers are paying for commercials to be sent to a large number of television viewers, when, in fact, only a small percentage of those television viewers may be target consumers. What is needed is an IPTV architecture that dynamically delivers different commercials to different viewers regardless of their location.